In-vivo bleeding may occur due to different diseases and in various locations along the gastrointestinal (GI) tract. This may indicate different pathologies present at those locations. For example, bleeding in the esophagus may be due to esophagitis or due to ruptures in varices. An ulcer in the stomach, small bowel or colon caused by inflammatory disease may be the source of bleeding. And, in the lower digestive tract, polyp or colorectal cancer may cause occult or overt bleeding. Therefore, early detection of bleeding and its anatomical location along the GI tract may be crucial for better treatment of many patients.
There are some known devices and methods, for detection of a bleeding source in the GI tract. For example, an endoscope or an imaging capsule endoscope may be used to search for and detect the source of an acute bleeding event in the GI tract. Such devices, however, may not be designed to efficiently detect the presence of small quantities of blood in the GI fluids. Other devices and methods may involve FOBT/FIT kits for detection of occult blood in the feces. However, while FOBT/FIT kits may detect bleeding that occurs in the colon, detection of bleeding in the small bowel or upper GI tract using FOBT kits is not efficient. Also, FOBT kits are not very patient friendly; patients are generally reluctant to perform such an examination.
PCT International Patent Application Publication No. WO 2010/086859, assigned to the common assignee of the present invention and incorporated herein by reference in its entirety, describes an in-vivo diagnostic device and method for detection of the presence of blood in GI fluids inside the GI tract. The in-vivo diagnostic device for detection of blood in the GI tract described therein comprises a special housing comprising a gap through which the in-vivo bodily fluids may flow. Illumination sources, such as LEDs, may reside on one side of the gap and may irradiate the bodily fluids passing through the gap. Each illumination source may irradiate the in-vivo fluids at a different narrow band illumination. At least one light detector may be positioned at the opposite side of the gap facing the illumination sources in order to detect light that passes through the in-vivo fluids. The device additionally comprises a transmitter for transmitting detected signals to an external receiver, which is a part of a system for the in-vivo detection of bleeding. The system also includes a processing unit for comparing the detected signals to a predetermined threshold, thereby determining the presence of blood in the GI tract.
However, the device described in the aforementioned PCT Application does not solve the problem of tissue entering the open gap. The tissue of portions of the GI tract, particularly—the small bowel, is collapsible, soft and covered with villi, and it snugly hugs the housing of the device as it progresses through the organ. The peristaltic motion of the organ pushes the tissue against the walls of the device and into the open gap. When tissue enters the gap, the tissue may block the passage of light from the illumination sources from reaching the light detector and may thus disrupt the operation of the device, for example, by leading to false readings of blood. Another deficiency is that the disclosed device does not address the problem of bubbles and content or non-fluid particles freely entering the gap, which may also disrupt the operation of the device, for example, by causing noise in the detected signals.
Furthermore, there are several other deficiencies in the aforementioned device disclosed in WO 2010/086859, for example a limited number of LEDs (preferably four) that does not allow differentiating between blood and other materials found in the bodily fluid of the GI tract, such as chlorophyll having the same absorption band between 600 nm and 700 nm as blood.
It has recently been found that there is also a problem of a relatively wide irradiation angle of LEDs located on the sensing head. In this case, light from such LEDs might strike objects (especially tissue) and change the reading in the photodiode.
It would be also beneficial to add temporal information to the system in order to identify active bleeding that occurred in the near past and to present a time line of the bleeding event. In other words, memory capability in the in-vivo diagnostic device and system are highly desirable.
There is, therefore, a need for improved devices, systems and methods for in-vivo detection of blood within in-vivo bodily fluids.